Surf. Sci. 482-485 (2001) pp. 1050-1055

Surface states and second harmonic generation at the (110) nickel surface from a first principles calculation

L. Calmels

Research Institute for Materials, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands

S. Crampin

Department of Physics, University of Bath, BA2 7AY, United Kingdom

J.E. Inglesfield

Department of Physics and Astronomy, University of Wales Cardiff, P.O. Box 913, Cardiff, CF2 3YB, United Kingdom

Th. Rasing

Research Institute for Materials, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands

Abstract
The electronic and magnetic structure of the ferromagnetic (110) nickel surface is calculated within the first-principles Layer Korringa Kohn Rostocker (LKKR) method. Spin-dependent results are given for the local density of states which show the existence of several empty surface states at the high symmetry directions of the surface Brillouin zone. Unoccupied surface states with their dispersion are described in detail and compared with inverse photoemission measurements. Second harmonic generation can be calculated in magnetic systems within the framework of the LKKR method. We present preliminary results which show that surface states are responsible for an enhancement of the second harmonic electric current in the vicinity of the (110) nickel surface. Such a surface state contribution to the second harmonic signal has recently been observed in Ni(110).